This is just for cases where there is no better solution at hand. And then still, only for pocket change. Just for quick and easy mobile spending, not to store large sums of money.
I'd only consider non-custodial wallets (where you control your own private keys) and HD wallets (for easy backup).
I like GreenAddress.it. It has packaged apps (which are all just packaged HTML & JavaScript) for Android, iOS, and Chrome for desktops, as well as being accessible from any modern HTML browser. They also have a still somewhat experimental
SPV wallet for Android called GreenBits, although it's missing some features available in the (non-SPV) GreenAddress.it apps/web page. It does support QR codes, even w/o one of the apps.
It may not be convenient enough for you though.... they never store your copy of your keys on their servers, so if you want to use it on a new device which doesn't have the keys already cached (and encrypted) locally, you need to type in (or scan) your full mnemonic. I see it as a security feature, but others may see it as an inconvenience.
The only other option I'd consider is Hive Web. It also has packaged apps for Android and iOS (but not for any browser), and can be accessed from any modern HTML browser. It also doesn't store your keys online (for better or worse).
Comparing the two, Hive has a simpler (IMO) interface than GreenAddress.it. On the minus side, it's not multisig and therefore can't offer 2FA nor GreenAddress's optional centralized "instant confirmations". It has no QR/camera integration, although it can display QR codes and it does support its
"waggle" address sharing feature with other nearby Hive users. It also doesn't support multiple accounts based on a single mnemonic, nor does it support read-only logins as GreenAddress.it does (which is nice for public terminals, as long as your OK with the potential loss of privacy). (FYI Hive for OS X is something completely different & incompatible.)
I wouldn't touch blockchain.info (for security reasons) nor BitGo (for
philosophical reasons).
Finally, although both Coinbase's and Coinkite's default wallets are custodial, they also have multisig options you may want to consider (I've never used either and so can't comment).
Just my 2¢....